Late 19th century technological advances for capturing whales, when combined with the expansion of processing capabilities in the early 20th century, created an industry that could catch and quickly render virtually any whale in any ocean. Here, using the current International Whaling Commission (IWC) database and other sources, we provide the fi rst accounting of the total global catch by industrial whaling operations in the 20th century. In sum, we estimate that nearly 2.9 million large whales were killed and processed during the period 1900–99. Of this total, 276,442 were killed in the North Atlantic, 563,696 in the North Pacifi c, and 2,053,956 in the Southern Hemisphere. The years 1925–39 in the Southern Hemisphere and 1946–75 in both hemispheres saw the highest totals of whales killed. For the entire 20th century, the largest catches were of fi n, Balaenoptera physalus, and sperm whales, Physeter macrocephalus, with 874,068 and 761,523 taken, respectively; these comprised more than half the total of all large whales taken. As noted in other publications, when one species began to decline, another was sought and hunted to take its place. In addition to reported catches, it is now known that the USSR conducted illegal whaling for more than 30 years. The true Soviet catch totals for the Southern Hemisphere were corrected some years ago, and a more recent assessment of the actual number of whales killed by Soviet factory fl eet ships in the North Pacifi c between 1948 and 1979 has provided us with more accurate numbers with which to calculate the overall global catch. The estimate for the total global catch by the USSR is 534,204 whales, of which 178,811 were not reported to the IWC. Introduction In the 1860’s, the Norwegian whaler and sealer Svend Foyn introduced the steam-powered whale catcher and the exploding harpoon gun to the whaling industry (Tonnessen and Johnsen, 1982). In the 1870’s, he improved upon shore-based factory processing to a level that came to be considered a standard for the industry (Tonnessen and Johnsen, 1982). By the time the 20th century began, the era of modern whaling—at least in the Northern Hemisphere—was well under way. Sixteen shore whaling stations had been established in Norway by 1883 (Risting, 1922; Dickinson and Sanger, 2005), and others were in operation in Newfoundland, Greenland, Russia, and Japan. In 1903, another Norwegian, Christen Christensen, introduced the fi rst factory ship, the wooden steamship Telegraf, into the waters off Spitsbergen (Tonnessen and Johnsen, 1982). Their primary targets were blue, Balaenoptera musculus; fi n, B. physalus; and humpback whales, Megaptera novaeangliae. However, industrial whaling south of the equator did not begin to resemble operations in the north until 5 years into the 20th century. Between 1900 and 1903, the only whales processed industrially were humpbacks caught via net and brought to a shore factory in Whangamumu Bay in New Zealand, a factory that had been established in 1890. The average catch was 8 whales per year during the 20-year operation of this factory (Lillie, 1915; Allison, 2012). The fi rst shore factory in the Southern Ocean was established in Grytviken (Cauldron Bay) on South Georgia Island by the Norwegian Carl Anton Larsen, from the Compania Argentina de Pesca, in late 1904 (Tonnessen and Johnsen, 1982). In 1903, one humpback whale was killed by modern methods by Adolf Andresen in the Straits of Magellan, but his processing station was not established until 1905 (Tonnessen and Johnsen, 1982). Thus, between 1900 and 1908, more whales were captured by industrial whaling methods in the Northern Hemisphere. By 1909, however, whaling south of the equator had surpassed that in the north. This trend continued until 1993, when the catch of whaling operations became comparable in the two hemispheres and were focused largely on minke whales, Balae“Some of the larger factory vessels with their capacity of over 2,500 barrels of oil per day capture more in two days than the original fl oating factories of 1904 were able to carry away with them in an entire season. One modern factory ship can take more whales in one season than the entire American whaling fl eet of 1846 which number over 700 vessels.” Lt (j.g.) Quentin R. Walsh, U.S.C.G., 1938